Traffic-signal-control mechanism



Aug. 6, 1929. c. w. NElLL TRAFFIC SIGNAL CONTROL MECHANISM Filed April 18, 1927 Patented Aug. 6, 1929.

UNITED STATES CHARLES W. NEILL, OI WASHINGTON, DISTRICT OF COLUMBIA.

TBAFFICLSIGNAL-CONTROL MECHANISM.

Application filed April 18, 1927. Serial No. 184,689.

My invention relates to improvements in mechanism foloperating signal lights for directing street trafiic.

The development in street 'traflic control is toward non-stop systems. In systems pro-. viding for non-stop trafiic it is necessary to use means for operating the signal lights so that the Go signal willin effect progress down the street ahead of the traffic. Such a system isclaimed. in application No. 45,334

and mechanism for operating signals according to.such a system is claimed in application No. 167,711.

The object of this invention is to'provide means whereby traffic signals may be operated from a central station according to the most approved non-stop systems. Another object of my invention is to provide means whereby all of the lights in each signal tower, i. e. the Stop, Caution, and Go lights, may be operated from the central station thru a single wire from the central station to each signal tower.

Further objects of my invention are to provide means for operating vtrafiic signal lights according to a non-stop system, which means shall be adjustable for the unequal distances between street intersections, the difference in traiiic volumes in di'lterent directions at various times of day and which shall be capable of adjustment to obtain slower speed for trafiici at such times as desirable. I

Other objects and advantages Will appear as the description proceeds.

, One embodiment of my invention is shown in .the accon'ipanying drawing which I shows an avenue having four intersecting streets, three of which are equipped with signal towers tor directing the traflic. The I switch mechanism at each tower and the mechanism at the central control station are shown, together with the wiring of the system.

The operation of the central control mech anism is as followsTwo commutator mechanisms 11 and 12 are rotated in opposite directions byfmotors 13 and 14. The speed of the motors 13 and 14 may be governed by the speed controls 15 and 16 The commutator mechanism 11 consists of a belt 17 running on spools 25. The belt 17 is a nonconductor, but has conductor contact strips or brushes mounted on the outside of it. Contact strips 18, 19, 20, and 65 comprise one set. Similar sets are equally spaced along the length of the belt as shown.

The commutator mechanism 12 is made up of 'anonconductor belt similar to belt 17, running on spools .26. Contact strips 22, 23, 24, and 66 comprise one of the sets of contact strips which are'evenly spaced along the length of belt 21. I

A guide bar 27 is rigidly mounted on a base plate 28. A guide bar 29 rests on thebase plate 28 and is free to slide on said base plate. Clamping members 30 connect the guide bars 27 and 29. Nuts 31 may be screwed up tOdItLW the guide bars 27 and 29 closer together. a

' Contact units 32, 33, 34, 35, 36, 37 38, and 39 rest on the base plate 28 and are held in position as shown by the clamping action of guide bars 27 and 29 thus forming a commutator. The contact units are setat the desired spacing from one another before the guide bars 27 and 29 are drawn against them by screwing up nuts 31.

The guidebars 27 and 29 are of some nonconducting material. The contact units are all similar and their construction will be understood by referring to contact unit .38. This contact unit consists of an insulating block 40 having contacts mounted on two sides of it, each of said contacts extending slightly above the top of the block 40 as shown. The contacts are the same size and equally spaced eicept for one long contact on one side whichextends the length of two of the short contacts on the opposite side. This construction is clearly shown in the drawing.

Contact units 32, 33, 34, and 35 when held in position form a commutator under commutator mechanism, 11 and will touch the belt 17. Cont-act strips 18, 19, 20, and 65 as they pass overcontact units 32, 33, 34,

and35 will close the circuit between the contacts which are mounted on opposite sides of the contact unit forpurposes which will appear as the description proceeds. Contact strips 22, 23, 24, and 66 will operate in a similar manner on contact units 36, 37, 38, and 39.

The invention is not in any way limited to the number of contact unit-s shown. The belts may be of any lengths and any number of contacts placed under them. Neither appear herea is it necessary that the contact units he arranged ina straight line. The lllYtJ'ltiUll is illustrated as shown in the drawing to simplify the mechanism and better explain the principle. It will at once be apparent, however, to those skilled in the art that arrangements such as radially set contact units set under solid disks instead of bolts would have practical advantages. Such mechanical details, however, would not be a change in the application of the principle but merely a substitution of mechanical parts.

All of the contacts on contact units 32, 33, 34, 36, 37, and 38 have wiresfrom them running thru a slot in the base plate 28. Contact units 35 and 39 have no wires running from them. Thesecontact units are not in, use in the system shown in the drawing but are to be wired in the event that the system be extended to include another streetintersection. I All of the cont-acts on the three contact side of-the contact units 32, 33, 34, 3G, 37, and 38 are wired to a power line 41. The middle one of each of these three contacts has a resistance placed in the circuit as illustrated. These resistances make the voltage on the middle contact less than that on the side contacts.

Both of the contacts on the two contact side-0t the contact units are wired to magnetic switches as illustrated. These switches are given reference characters 42, 43, 44, 45, 46, and 47 in the drawing. It will be noted thatswitches 42 and both connect with a wire which runs down the avenue to switch unit 48. Magnetic switches 43 and 46 both connect to a, wirewhich runs down the avenue to switch unit 49. Magnetic switches 44 strip 20 have passed across contact unit 34.

The reason for keeping this switch closed in this way is to prevent the avenue trathc (to signal from changing to Stop ust a few seconds before the other ci'mmmtator tact strip 19 closes the circuit between the middle contact and the long contact.

lVhen contact strip 19 closes the circuit between the middle contact and the long contact of contact unit 34 the circuit will be complete from power line 41 through the resistance, through the said contacts of contact unit; 34 and through the magnet of magnetic switch 47 and down theavenue to'switch unit 50.

Vlltlt contact strip 18 closes the circuit between the nearest contact and the long contact of contact unit 34 the circuit is the same as for contact strip 19 except that the resistance between the power line 41 and contact unit 34 is cut out. Contact strip 65 has'the same effect as had contact strip 19. Thus as the set of contact strips pass over contact unit 34, contact strip 20 will cause avoltage to be transmit-ted to switch unit if the avenue Go light is lit in signal tow er 53. Contact strip 19 will cause a reduced voltage, the value of which will dependon the amount and 47 both connect to a wire which runs of resistance in the circuit, to be transmitted down the avenue to switch unit 50.

The operation of the commutator mocha-'- nism 11 is as follows: The belt is driven in the'dir'ection indicated by the arrow. .When the first strip 20-of a set of contact strips gets into position over contact unit 34 the circuit between the two furthest contacts will be closed. The circuit will then be complete from the power line 41 to the armature of magnetic switch 44 and if this switch is closed the circuit will run through the magnet coil of the switch and then down the avenue toswiteh unit 50 which operates signal tower 53. The reason for'making this circuit' throu h the magnetic switch will er. It the magnetic switch is open, {is shown in the drawing then closing the circuit as far as the armature will have. no effect. 'Butif theGo light, for non-stop cavenue traffic, in signal tower 53 is lit by connnutator mechanism 12, then magnetic; switch 44 will be closed and when "contact strip 20 closes the circuit as described, magnetic switch 44 will be kept closed until all of the contact strips in the set with contact -nue is operated by a switch .unit.

to switch unit 50. Contact strip 18 will cause the full line voltage to be transmitted to switch unit 50 and the current flow with this voltage will cause magnetic switch 47 to close. Contact strip will cause the reduced voltage to again be impressed on switch unit 50.

The contact strips on both commutator mechanisms operate onf'th e contact units.

which they pass over in a manner similar to the operation described in connection with contact unit 34; one contact unit of each commutator mechanism affecting one of the switch units along the avenue.

Each of the signal towers along the ave- Switch unit 48 which operates signal tower 51 is shown in detail in the drawing. The signal towers shown each have three lights. Referring to signal tower 51; the upper light 54 so contact unit 34 ten seconds before the con indicates Go to traflic on the avenue and nal tower 51 are operated by switch unit 48.'

The switch unit 48 consists of a magnet 57, armatures 58 and 59 and adjustable contacts 60, 61, 62, and 63. The magnet 57 is excited whenever a voltage is impressed on the wire connecting switch unit 48 with the commutator mechanisms 11- and 12 at the central control station. \Vhen the low on reduced voltage is impressed on magnet 57 the magnet is excited sufliciently todraw up the armature 58 against the tension of a spring which normally holds this armature away from the magnet. Then the full line voltage is impressed on magnet 57 it is excited so that it draws upbot-h armatures against their springs which hold them normally away from the magnet.

Armature 58 is wired to a power line 64 which runs thelength of the avenue and provides power to light the signal lights. Armature 59 is wired to adjustable contact 61.

When the magnet 57 is not excited the armature 58 will he held against adjustable contact 60, and armature 59 will be held against adjustable contact 63. The circuit will then be from the power line 64 to armat-nre 58 and through adjustable cont-act 60 to signal light 56 and a Stop signal will be given to the trafiic on the avenue and a G signal to cross traflic.

\Vhen the reduced voltage causes magnet 57 to become excited armature 58 will be drawn against adjustable contact 61 while armature 59 will remain against adjustable contact 63. The circuit will then be from the power line 64 through armature 58; adjustable contact 61; armature 59; adjustable contact 63 to signal light and the Cantion signal will be lit. A W hen the full line voltage causes magnet 57 to become excited, armatures 58' and 59 will be drawn against adjustable contacts 61 and 62 respectively. The circuit will then be from power line 64 through armature 58 adjustable contact 61; armature 59; adjustable contact 62 to signal light 54 and the Gosignal will be given to trafiic on the avenue and a Stop signal to cross traffic.

If both armature's are drawn up close to the magnet 57 and the voltage on the magnet drops to the reduced.volt-age armature 59 will be pulled by the tension of its spring away from adjustable contact 62 and against adjustable contact 63 and the-Caution light will again be lit.

For the proper operation of the armatures 58 and 59 it is necessary that they should not be too far away from the magnet when the magnet is not excited and they should never come into actual contact with the core of the magnetor residual magnetism might hold them. The adjustment of armature 59 is especially important since if it is too close when away from the magnet it will be drawn up when the reduced voltage is on the magjust described. The wiring of signal-towers 52 and 53 to their switch units is omitted for the sake of simplicity.

From the foregoing description the working of the invention should be clear, but a .i'ew general remarks on its operation will doubtless be helpful to better understand it.

The speed with which the belts 17 and 21 travel will determine the speed with which the non-stop traffic may move up and down .the avenue. The reason for the speed adjust ments 15 and 16 on the dr ving motors 1s to vary the speed of the belts and consequently of the trafiic. A slower speed would be desirable in slippery weather. The speed of the up trafiic may be regulated independently ot the speed of the down traffic. It might be desirable to allow the trafiic in the direction of the least travel to run faster, since there could be more space between vehicles.

It will be noted that belt 17 has more con-' tacts on it than has belt 21. Thus if belt 17 is operating the progressive signal for traffie moving down the avenue then due to this larger number of contacts more non-stop trafiic can move down the avenue than can move up. If the avenue is one of the thoroughfares leading to the suburbs there will be more trafiic coming one way in the morning, and'in the late afternoon the'bullcof trail-1c would be the other way. Belts might be interchanged to get the larger number of contacts operating the signals for the bulk of the trafiic. When traflic in both directions is equal, belts with equal numbers of contacts could be used.

' On one-way streets the second commutator mechanism at the central control station would not be necessary. I

The non-stop traific may move at a uniform speed it the distance between the contact units 32, 33, 34, 36, 37, and 38 at the cen-- tral control station is proportional to the dis tance between the signal towers-on the avenue. If higher or lower speed between certain signal towers is desiredit may be made possible by making the distance between the contact units at the central station which operate these signals towers smaller or greater respectively.

Operation of the signal towers from the central control station would be possible without a switch unit at every tower, but

by using the switch units it is possible to have only one wire from the central control station to each signal. Without the switch units 48, 49, and 50 more wires to each signal tower would be necessary and where the distance was great the expense would be very large. However this use of the communot 57, the springs will hold armatures 58' tator mechanisms is within the scope of the invention since the substitution of two consignal tower 51 through contact units 32 and- If there is no contact strip or brush across either of these contact units 32 and.

36, there will be no power furnished to magand 59 back and the Stop signal to traflic on the highway, and the Go signal to cross tratiie, 56, will be lit, 115111,: abelt such as belt 17 in which the contact strips or brushes are as closely spaced as shown, there will be no time when there is not some one of the contacts across contact unit 32. lVith contact strips spaced as shown on belt 21, however, there will be short intervals when there is no contact strip across contact unit 36.'

The passing of the contact strips or bushes 20, 19, 18 and 65, on'belt 17 over contact unit 32, comprises a cycle of operation of contact .unit 32 as follows:

As indicated in the drawing this belt turns in a clockwise direction and contact strip 20 will first close the circuit between the two furthest contacts on contact unit 32. If magnetic switch 42 is open as shown in the drawing, contact strip 20 will have no effect and unless power is being furnished to magnet 57 by commutator mechanism 12 the springs will hold armatures- 58 and 59 back, causing the highway Stop signal and cross trafiic Go signal 56 to be lit.

WVhen contact strip 19 closes the circuitbetween the middlev right hand contact andthe long left hand contact of contact unit 32,

power will be furnished to magnet 57 with the resistance in circuit as shown in the drawing. This low voltage on magnet 57 will cause light armature 58 to be drawn up against magnet 57 and the Caution light 55 in signal tower 51 to be lit.

When contact strip 18 crosses contact unit 32 and closes the circuit between the forward right hand contact and long left hand contact of contact unit 32 the full voltage of A cycle of operation of the contact strips on belt 21 over contact unit 36 will be identical with the operation above described.

Contact strip 20 on belt 17 and contact strip 24 on belt 21 have no etfect on the operation of the signals unless magnetic switches 42 or 45, respectively, are closed. Magnetic switch 42 will be closed when commutator mechanism 12 is operating the highway Go signal 54. Then magnetic switch 42 is thus closed and contact strip 20 crosses contact unit 32, contact strip 20 will operate the highway Go signal until contact strip 18- crosses contact unit 32 to operate the highway Go signal. i

Y Contact strip 24 on belt 21 operates in the same way on contact unit 36 if the highway Go signal is being operated by commutator mechanism 11 and magnetic switches 45 thereby closed when contact strip 24 crosses contact unit 36.

The object of this interrelation between the two commutator mechanisms through the magnetic, switches is to prevent impractical short c oss traffic Go periods as was fully dcscrib d before. I

I claim: 4

1. In a traflic signal system for regulating trafiic on a highway intersected by a plurality of differently spaced cross streets electric signal means for each intersection including Go-Stop signals for the highway and for the cross. streets respectively, a "central control station, conductors extending from the signal meansto the central control station and terminating in relatively stationary contact means having contacts for each signal means, cyclic commutator means having contacts cooperating with said first named contacts and driving means operating at a uniform speed to produce the effect of a progres sively travelling Go signal along the highway, said'relatively stationary contacts being spaced in accordance with the different distances between the cross streets.

2. In a traflic signal system for regulatmg traflic on a highway intersected by a plurahty of cross streets, electric signal means for each intersection including Go-Stop signals for the highway and for the cross streets respectively, a central control station, conductors extending from the signal means to the central control station and terminating in relatively stationary contact means haying contacts for each signal means, cychc commutator mean s having conta'ctscooperating with said first named contacts and driving means operating at a uniform speed to produce the effect of aprogressively trav: 5 elling Go signal along the highway, said relatively stationary contact means including means for adjusting the spacing between the contacts corresponding to the several sig-v Ilals with relation to the direction of the movement of the commutator means to change the timing of the signals.

' 3. In a traflic signal system for regulating traflic on a highway intersected by a plurality of cross streets, electric signal means for each intersection including Go-Stop signals for the highway and cross streets respectively, a central control station, separate connections "between each of said signal means and said central control station, com- 0 mutator mechanism in said central control station, and means to operate said commutator mechanism to change the signals progressively in oppositedirections along the highway and to give signals to traffic in both 5 directions on said cross streets.

4. Iii a traflic signal system for regulating traflic on a highway intersected by a plurality of cross streets, electric signal means for each intersection including Go-Stop sig nals for the highway and for the cross streets respectively, a central control station, a conductor extending from each of said signal 'means tothe central control station and terminating in contact means thereat, commu tator mechanism in said central control station in operative relation to said contact means, operating means for moving said commutator mechanism and said contact members with respect to each other to change the signals progressively in opposite directions along the highway, and to give signals to traflic in both directions on said cross streets. v

In a traffic signal system for'regulating traflic on a highway intersected by a plurality of cross streets, electric signal means for each intersection including Go-Stop signals for the highway and for the cross streets respectively, a central control mechanism comprising contacts arranged ina group, one of said contacts being connected with each individual signal means along the highway, commutator mechanism in operative relation to said group and driving means therefor to produce the effect of a progressively :traveling Go signal up the highway, a second group 7 of contacts, one of said contacts being con nected with each individual signal means along the highway, and a'secondcommutator mechanism in' operative relatlon 'to sand. group and driving means therefor to produce' the efl'ectof a progressively travelling Go signal down the highway, both of sai d commutator mechanism including means for giving signals to cross traflic and means to prevent a .Go signal to cross traffic when the beginning of the Go period by one connnutator mechanism follows the end of the Go period by the other commutator mechanism by less than a predetermined time interval.

16. In a trafiic signal system for regulating traffic on a highway, intersected by a plurality of'cross streets, electric signal means for each intersection comprising a common Go and a'common Stop signal for both directions along the highway, a central control nals for the highway and cross streets respectively, a central control station, a conductor from each of said signal means to said central control station terminating in contact means thereat, commutator mechanism cooperating with said contact means and means driving said commutator mechanism to produce the efiect of a progressively travelling Go signal up the highway, a second commutator mechanism cooperating with said contact means and means driving said second commutatorme'lchan'sm to produce the effect of a progressivel travelling Go signal down the highway, both'of said commutator mechanisms operating the same set of signals.

8. In a traffic signal system forgregnlating trafiic on a highway intersected by a plurality of cross streets, electric signal means for each intersection including common. G0-

7 signals for both directions alongthe highway, a central control station, a separate conductor from each signal means to said central control station, each conductor terminating in a pair of contact units, all of the said contact units at the central control station-being divided into two groups and each signal means having one of its contact units in each group, commutator mechanism for each group of contact units for operating said signal means from said conductors, and means for operating said commutator mechanisms, both of said commutator mechanisms operating thecommon set of signals.

9. In a trailic signal system for regulating traflib on a highway intersected by a plurality of cross streets, electric signal means for each intersection including Go-Stop signals for the highway and cross streets respectively, a central control station, a separate connection between each of said signal means and said central control station, com- ,in'utator mechanism and driving means therefor in said central control station for the individual signal means to produce the operating on said connections to the indicfiect of a progressively travelling Go signal vidual signal means to produce the effect of down the highway, signals for cross trafiic a progressively travelling Go signal up the operated by both the said commutator mech- 5 highway, other commutator mechanism and anisms jointly.

driving means therefor in said central 0011- In testimony whereof I aifix my signature. trol station operating on said connections to I CHARLES W. NEILL.

. Disoimm MER 1,7 23 ,O62.-0harles W. N eiZZ, Washington, D. C. Tn iFIo-SmnAuCoNTmL MECH- ANrsM. Patent'dated August 6,1929. Disclaimer filed December 16, 1 981, by the ass gnee', Grouse-Hindsompany. Hereby enters this disclaimer restricting-claims 3 and a as follows By restricting the limitation and to give signals to tratfic in both directions on said cross streets of said claim 3 to and to gi/ve like signals simultaneously to t'rafic in both directions on said cross streets. 1 By restr'qting the limitation and to give signals to traffic in both directions on said cross stree siof said claim 4 to and to glee like signals'simaltaneoasly to Mafia in both directions on said eross streets. [Ofiozal Gazette Janua1y5, 1932.] 

